I have Revel F36 and are/were dreaming of a xxxBe model for better directivity and avoid the aluminium tweeter break-up ringing at 22k.
But I was hoping Revel would fix the 7-9khz dip in the treble for 228, I am not too interested in buying a premium speaker with such deviations. I do not want a worse treble...Revel should to improve the tweeter/waveguide , beryllium only is not enough. Maybe I should dream of a KEF instead...
By the way, you need to go to the Be range to avoid electrolytic capacitors in the crossover...
Here is my F36 in room, with and without "room correction DSP". Mooving Mic Method Pink noise RTA 1/48. DSP Target curve in bottom of plot
Single point measurement:
F36 Tweeter check. Singe point sweep 1/6
The Be tweeter in 228 does not seem to be worth the money